SAW Sensor Ice Detection on Air Data Probes

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Solution Overview

Problem

Ice accumulation on air data probes interferes with the accuracy of air data measurements, posing flight safety challenges due to erroneous data input and potential damage from ice shedding.

Innovation Solution

Integration of surface acoustic wave (SAW) sensors on air data probes to detect particulate accumulation, including ice, by sensing small changes in mass load, with signals sent to circuitry for proactive de-icing and predictive maintenance, and synchronization with on-board systems for health management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If air data probes are mounted on exterior surfaces to gain exposure to external airflow, then measurement capability is improved, but ice particle accumulation occurs causing measurement accuracy to deteriorate

Engineering Contradiction:

Improveair data measurement accuracyVSAvoidice particle accumulation

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implementing ice detection before significant ice accumulation occurs. The system uses optical sensors to detect ice particles in the airflow and acoustic sensors to detect ice accumulation on the probe surface, triggering de-icing activation before ice blocks the probe or degrades measurements beyond acceptable limits.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback through a closed-loop control system that continuously monitors ice conditions using optical and acoustic sensors, compares readings against thresholds, and adjusts heater activation accordingly. The system provides feedback signals to control de-icing activation, ensuring measurements remain accurate while avoiding unnecessary heater operation.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If de-icing heaters are activated to prevent ice accumulation, then measurement accuracy is maintained, but energy consumption increases

Engineering Contradiction:

Improveair data measurement accuracyVSAvoidheater energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system activates de-icing heaters only when ice accumulation is detected by optical or acoustic sensors, rather than operating continuously. This preliminary detection approach allows the system to maintain measurement accuracy by activating heaters only when needed, significantly reducing unnecessary energy consumption during ice-free conditions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The feedback control system continuously monitors ice detection sensor outputs and adjusts heater activation in real-time. When sensor readings indicate no ice presence, the system shuts off heater power; when ice is detected, the system activates heaters to maintain measurement accuracy, optimizing the balance between measurement precision and energy consumption.

Inventive Principle:

Principle #23Feedback

3Reliability

If multiple sensors are deployed on the air data probe, then detection reliability is improved, but device complexity increases

Engineering Contradiction:

Improveice detection reliabilityVSAvoidsensor system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the ice detection function into two distinct sensing modalities: optical sensors for detecting ice particles in the airflow and acoustic sensors for detecting ice accumulation on the probe surface. This segmentation allows each sensor type to specialize in detecting specific aspects of ice conditions, improving overall detection reliability while maintaining manageable system complexity through modular sensor placement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system achieves multi-functionality by using a combined optical-acoustic sensing approach where optical sensors detect incoming ice particles and acoustic sensors detect accumulated ice on the probe. This universal detection capability covers both pre-accumulation and accumulated ice conditions, enhancing reliability without requiring separate specialized systems for each detection mode.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables early detection and warning of icing conditions, improving flight safety and reliability by preventing erroneous data input and optimizing heater usage, while maintaining system efficiency through proactive maintenance.

Implementation Method 1

surface acoustic wave sensors for detecting particle accumulation in the atmosphere or in gases

Methodology Applied

Scientific EffectSurface acoustic wave: Surface Acoustic Wave

Implementation Method 2

sensing small changes in mass load

Methodology Applied

Scientific EffectMass load sensing:

Data Source

PatentEP4016088B1Surface acoustic wave sensors for air data probes

Publication Date: 2023.11.15 HAMILTON SUNDSTRAND CORP

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AI summary

An air data system (10) includes an air data probe (12) and a surface acoustic wave (SAW) sensor (68, 70, 72, 74, 76, 78, 80) attached to the air data probe for detecting particulate accumulation. The air data probe (12) includes a probe head (52), a strut (54) connected to the head, and a mounting plate (56) connected to the strut. The probe head has an inlet, an interior surface extending from the inlet, and an exterior surface extending from the inlet.